What does soil pH measure?

Soil pH primarily measures the acidity or alkalinity of the soil. It reflects the concentration of hydrogen ions present in the soil solution, which directly influences the soil's chemical reactions, including nutrient availability. The soil pH scale ranges from 0 to 14, with values below 7 indicating acidity, above 7 indicating alkalinity, and exactly 7 considered neutral. Understanding soil pH is crucial for nutrient management because it affects the solubility and availability of essential nutrients to plants. For example, most nutrients are optimally available to plants when the soil pH is between 6 and 7.5.

The other options focus on different characteristics of soil. Soil texture relates to the size and distribution of soil particles and affects drainage and retention. Soil fertility encompasses a broader aspect of the soil's ability to provide necessary nutrients for plant growth but is not specifically measured by pH alone. Soil nutrient content indicates the actual amount and types of nutrients present but does not directly reflect how those nutrients interact in relation to soil pH. Understanding pH is key in nutrient management because it informs how to adjust the soil environment to promote the best possible conditions for crop growth.